Examine source code of Private Tabs Toggle

{
  "manifest_version": 2,
  "name": "Private Tabs Toggle",
  "version": "1.0",
  "description": "Quickly open a new private tab.",
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_title": "Open Private Tab",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c9f8883c-64d2-4687-a912-1ab4c7542fac}"
    }
  }
}